[cisco-nas] Using private subnet for dial up customers

[Rodney Kreisler]

We are a small ISP.  One of our offerings is dial up internet access.  
We use AS5300 NAS.  Currently these are configured to assign IPs from 
our pool of public IPs.

Is it possible, or even advisable, to use a private subnet for dial up 
customers rather than public IPs?

If so, would a separate router be needed or can the AS5300 handle the 
translation and how would it be configured?

TIA

Rod